Conventional semiconductive chips include many active devices, i.e., transistors and diodes, as well as inactive devices, i.e., resistors and capacitors. These semiconductive chips include a plurality of bond pads, which are metallized areas on the periphery of the semiconductive chip for making a connection to a package pin. A small diameter gold or aluminum wire is bonded each of to the bond pads by application of heat and ultrasonic energy. Each of these bond wires electrically connects the semiconductive chip with a circuit or component of a substrate. In an effort to decrease the space occupied by semiconductive chips and the assembly steps associated with such semiconductive chips, flip chip solutions have become more prominent because they do not require wire bonding.
A conventional flip chip is essentially a semiconductive die with all terminations on one side of the chip in the form of solder bond pads or bump contacts. The surface of the flip chip having the bond pads is flipped over for attaching to a matching substrate in which interconnecting thin films and possibly also thin film components have previously been deposited. All electrical connections between the flip chip and the substrate are made simultaneously by applying heat or a combination of ultrasonic energy and pressure. With such conventional flip chips, the bond pads are not located on the active devices of the chip. Rather, the bond pads are intentionally located away from the active devices. See, for example, Column 4, lines 53-57 of U.S. Pat. No. 5,764,486. The bond pads are located away from the active devices because fabrication of the bond pads or attachment of contact studs to such bond pads may damage the active device if the active device is located underneath the bond pad. For example, the bonding of a contact stud (a rigid electrical conductor) to the bond pad of the flip chip may crack a transistor if the bond pad is located on the transistor, rendering the chip inoperable or significantly decreasing its reliability.
Despite the known drawbacks of locating bond pads on active devices of chips, attempts have been made to locate specially configured bond pads directly over some transistors. For example, one conventional flip chip includes a specifically configured gold bump located on a transistor cell of a chip. The gold bump is formed by depositing a 20-50 micron layer of gold on top of the transistor cell with an electroplating process. The gold bumps can then be bonded, such as soldered, to a matching substrate. However, fabrication of these gold bumps problematically requires several manufacturing steps, further complicating the construction of the flip chip.